A self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy

Abstract

The present invention discloses a self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy, which comprises a supporting self-floating base and a water-absorbing evaporation component. An installation hole is formed in the center of the supporting self-floating base, and the water-absorbing evaporation component is arranged at the central position of the supporting self-floating base in a penetrating manner, and the water-absorbing evaporation component is closely fitted with the supporting self-floating base; the water-absorbing evaporation component can absorb sunlight and utilize wind energy to achieve seawater evaporation, and can prevent the accumulation of salts generated by seawater evaporation; through structural design, on the one hand, the evaporator can maximize the absorption of solar energy and convert it into heat energy for heating seawater. On the other hand, the wind can smoothly pass through the surface of the evaporator, taking away water vapor and accelerating the evaporation process. The auxiliary effect of wind energy can effectively supplement the deficiency of solar energy and ensure that the evaporator can still work efficiently under all-weather and different climate conditions.

Description

Technical Field

[0001] The present invention relates to the technical fields of interfacial water evaporation, seawater desalination, and sewage treatment, and particularly relates to a self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy. Background Art

[0002] As an important means to solve the global water shortage problem, seawater desalination technology has received extensive attention in recent years. Most of the existing seawater desalination technologies rely on solar energy as the main energy source, using solar radiation to heat the water body, promoting water evaporation, and thus achieving water separation. However, solar energy is not an all-weather available energy source. Especially on cloudy days, rainy days, or at night, the availability of solar energy is severely restricted. Therefore, in order to ensure that the seawater evaporator can still operate efficiently under all-weather and variable weather conditions, it is necessary to introduce auxiliary energy to supplement the insufficient part of solar energy.

[0003] As a clean and all-weather energy source, wind energy can effectively utilize the wind in the natural environment to accelerate the evaporation process. When the wind blows over the surface of the evaporator, it can carry away the water vapor on the surface, thereby reducing the vapor pressure on the surface of the evaporator and promoting further evaporation of water. Based on this, designing a seawater evaporator that can maximize the absorption of sunlight and ensure smooth passage of wind through its surface has become an important goal for improving evaporation efficiency and expanding the application range.

[0004] In the practical application of seawater desalination, salting-out phenomenon will inevitably occur on the surface of the evaporator. As the evaporation process continues, salts will gradually accumulate on the surface of the evaporator because in the seawater environment, the water contains abundant dissolved salts. As the salt layer gradually thickens, the heat conduction and evaporation performance of the evaporator surface will decrease significantly, and may even lead to a serious decline in the system efficiency. Therefore, solving the problem of salting-out accumulation and preventing salts from accumulating on the surface of the evaporator for a long time is the key to ensuring the long-term stable and efficient operation of the evaporator.

[0005] To solve this problem, it is particularly important to design an evaporator structure with self-cleaning function. The self-cleaning function can enable the salts precipitated on the surface of the evaporator to quickly fall back into the water body through specific structural design, rather than forming a thick salt layer on the surface of the evaporator, thereby avoiding the impact of salt scaling on the evaporation performance. In addition, the evaporator should also have the ability of self-floating, which can enhance the contact between the evaporator and the water body and provide guarantee for the self-cleaning mechanism. During the floating process of the evaporator, the salts precipitated on the surface can more easily come into contact with and dissolve in the water body under the action of gravity, reducing the risk of salt accumulation.

[0006] Therefore, designing a self-floating and self-cleaning solar-wind dual-energy-driven seawater evaporator has become a technical challenge in the field of seawater desalination. This design not only requires the evaporator to have good solar absorption capacity, but also to be able to effectively utilize wind energy to promote the emission of water vapor; when dealing with salting-out problems, it is also necessary to ensure that the surface of the evaporator can remain clean to continuously maintain high evaporation performance.

[0007] Generally speaking, how to ingeniously integrate solar energy, wind energy, the self-floating ability and self-cleaning function of the evaporator is the key technical difficulty in designing an efficient, stable and adaptable seawater evaporator. Solving these problems will provide a more efficient, economical and sustainable solution for the practical application of seawater desalination technology. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention proposes a self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy.

[0009] The technical solution of the present invention is as follows:

[0010] A self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy, including a supporting self-floating base and a water-absorbing evaporation component. An installation hole is provided in the center of the supporting self-floating base, and the water-absorbing evaporation component is inserted through the center of the supporting self-floating base and is in close fit with the supporting self-floating base; the water-absorbing evaporation component can absorb sunlight and at the same time can utilize wind power to realize seawater evaporation, and can prevent the accumulation of salts generated by seawater evaporation.

[0011] Further, the supporting self-floating base is made of foamed PLA material, and the whole adopts a hollow structure. An inverted quadrangular pyramid is dug out in the center to form an installation hole.

[0012] Further, the density of the water-absorbing evaporation component is greater than the density of water, so that the water-absorbing evaporation component can be firmly combined with the supporting self-floating base.

[0013] Further, the bottom of the water-absorbing evaporation component extends out of the supporting self-floating base and is immersed in seawater, and the top of the water-absorbing evaporation component is exposed above the supporting self-floating base and exposed to the air.

[0014] Further, the water-absorbing evaporation component adopts an inner and outer petal structure, including an inner petal component and an outer petal component. The inner petal component and the outer petal component are each in a V-shaped structure as a whole, and the V-shaped structure is a parabola with an upward opening in the part below the self-floating base and a straight line in the part inside and above the self-floating base.

[0015] Further, the upward-opening parabola formula of the inner petal component is: ; The upward-opening parabola formula of the outer petal component is: ; The straight line of the inner flap component forms an angle of 67.5 to 75° with the horizontal line, and the straight line of the outer flap component forms an angle of 45 to 67.5° with the horizontal line.

[0016] Furthermore, the preparation process of the water absorption and evaporation component is as follows:

[0017] Step 1): Put an appropriate amount of PVDF powder and GNP powder into an electrothermal blast drying oven at 65 - 75°C and dry for 25 - 30 minutes to remove moisture and ensure complete drying;

[0018] Step 2): Add 9.5 grams of dry PVDF into a beaker containing 50 milliliters of DMA. Put the beaker into a heat - collecting type constant - temperature heating magnetic stirrer and stir in a water bath at 70 - 80°C for 2.5 - 3.5 hours until the PVDF is completely dissolved to obtain a colorless and transparent PVDF solution;

[0019] Step 3): Add 0.5 grams of dry GNP into the PVDF solution, continue to stir in a water bath at 70 - 80°C for 2.5 - 3.5 hours. After that, take it out and perform ultrasonic dispersion for 25 - 30 minutes to obtain a uniformly dispersed black composite solution; then cover the solution with a breathable membrane and let it stand at room temperature for 7 - 9 hours to remove bubbles for further use;

[0020] Step 4): After the defoaming process is completed, use a syringe to inject the black composite solution into the mold to completely fill it; after the mold is sealed, pre - cool it in a refrigerator at about 3 - 5°C for 5 - 7 hours to prevent cracking during the actual freezing process; after pre - cooling, put the mold into the cold trap of a vacuum freeze - dryer and freeze it at - 65 - 70°C for 1.5 - 2.5 hours;

[0021] Step 5): After complete freezing, obtain a 3D solid composite by disassembling the mold;

[0022] Step 6): Put the solid composite back into the cold trap and freeze - dry it at - 65 - 70°C and 0.1 Pa for 2.5 - 3.5 hours to sublime the DMA solvent and form a 3D water absorption and evaporation component.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1) Dual - drive structure of solar energy and wind energy: Through structural design, on the one hand, this evaporator can maximize the absorption of solar energy and convert it into heat energy for heating seawater. On the other hand, it enables the wind to pass smoothly through the surface of the evaporator, taking away water vapor and accelerating the evaporation process. The auxiliary role of wind energy can effectively supplement the shortage of solar energy, ensuring that the evaporator can still work efficiently all - day long and under different climate conditions.

[0025] 2) Self-floating structure: Through the use of lightweight materials and a reasonable buoyancy design, the evaporator can float on the water surface by itself; this self-floating structure guarantees the self-cleaning function and the self-adaptive wind direction function of the evaporator.

[0026] 3) Self-cleaning structure: In a seawater environment, salting out inevitably occurs on the surface of the evaporator. As the working time extends, salts will gradually accumulate and affect the evaporation efficiency. Through a special structural design in the present invention, the surface of the evaporator has a self-cleaning function. When salts precipitate and deposit on the surface of the evaporator, due to the self-floating structure and the action of gravity, the precipitated salts can automatically fall off into the water body below, avoiding excessive accumulation of salts, keeping the surface of the evaporator clean, and ensuring stable evaporation efficiency.

[0027] 4) The water-absorbing evaporator component adopts a double-layer structure of inner and outer petals, where the inner petal is long and the outer petal is short. The existence of the outer petal increases the evaporation area of the interfacial water, thus being more conducive to improving the evaporation rate of the evaporator; the inner and outer petal structure of the water-absorbing evaporation component, and the part below the self-floating base is a parabola with an upward opening, ensuring that the area of the evaporator underwater is as large as possible, so that its water absorption is more sufficient; the part inside and above the self-floating base is linear, ensuring a more stable match with the support of the self-floating base. Description of the Drawings

[0028] Figure 1 is the overall three-dimensional structure schematic diagram of the present invention;

[0029] Figure 2 is the front structure schematic diagram of the present invention;

[0030] Figure 3 is the side structure schematic diagram of the present invention;

[0031] Figure 4 is the structure schematic diagram of the support self-floating base of the present invention; Figure a is the three-dimensional structure diagram; Figure b is the cross-sectional view in the length direction; Figure c is the cross-sectional view in the width direction;

[0032] Figure 5 is the physical diagram of the water-absorbing evaporation component of the present invention;

[0033] Figure 6 is the preparation flow chart of the water-absorbing evaporation component of the present invention;

[0034] Figure 7 is the schematic diagram of the principle of absorbing sunlight of the present invention;

[0035] Figure 8 is the schematic diagram of preventing salt accumulation of the present invention;

[0036] Figure 9 is the schematic diagram of the principle of utilizing wind energy of the present invention;

[0037] Figure 10 Schematic diagram of self-rotation of the present invention;

[0038] In the figure: 1. Support self-floating base; 101. Mounting hole; 2. Water absorption and evaporation component; 201. Inner flap component; 202. Outer flap component. Specific implementation mode

[0039] The following further describes the present invention in conjunction with the accompanying drawings of the specification.

[0040] The technical problem to be solved by the present invention is how to maximize the absorption of sunlight, effectively utilize wind power, and prevent the problem of salt accumulation caused by long-term evaporation in seawater.

[0041] The whole of the present invention consists of two parts, one part is the water absorption and evaporation component 2, and the other part is the support self-floating base 1.

[0042] The overall preparation process is completed in three steps.

[0043] The first step: Preparation process of the water absorption and evaporation component:

[0044] Such as Figure 6As shown in the figure, first, an appropriate amount of PVDF powder (polyvinylidene fluoride (powder, high viscosity, high mechanical properties, extrusion molding), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) and GNP (nano graphite powder, D50 < 400nm, metal-based ≥ 99.95%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.) were placed in an electrothermal blast drying oven at 70°C for 30 minutes to remove moisture and ensure complete drying. Subsequently, 9.5 grams of dried PVDF was added to a beaker containing 50 milliliters of DMA (analytical grade, content (GC) ≥ 99.0%, purchased from Sinopharm Chemical Reagent Co., Ltd.). The beaker was placed in a thermostatic heating magnetic stirrer with a heating coil, and stirred in a water bath at 75°C for 3 hours until the PVDF was completely dissolved, obtaining a colorless and transparent PVDF solution. Then, 0.5 grams of dried GNP was added to the PVDF solution, and stirring was continued in a water bath at 75°C for 3 hours. After that, it was taken out and ultrasonically dispersed for 30 minutes to obtain a uniformly dispersed black composite solution. Then, the solution was covered with a breathable membrane and left to stand at room temperature for 8 hours to remove air bubbles for further use. After the defoaming process was completed, the black composite solution was injected into the mold using a syringe to completely fill it. After the mold was sealed, it was pre-cooled in a refrigerator at about 4°C for 6 hours to prevent cracking during the actual freezing process. After pre-cooling, the mold was placed in the cold trap of a vacuum freeze dryer (model ZLGJ-10 purchased from Zhengzhou Fanjing Technology Co., Ltd.) and frozen at -70°C for 2 hours. Once completely frozen, the 3D solid composite was obtained by carefully disassembling the mold. Finally, the solid composite was placed back into the cold trap and freeze-dried at -70°C and 0.1 Pa for 3 hours to sublime the DMA solvent, forming a 3D water-absorbing and evaporating component. The structural diagram is as shown in Figure 1 as shown in the figure, and the effect diagram is as shown in Figure 5 the figure.

[0045] The water-absorbing and evaporating component 2 adopts an inner and outer petal structure, including an inner petal component 201 and an outer petal component 202. The inner petal component 201 and the outer petal component 202 as a whole are respectively in a V-shaped structure, and the part of the V-shaped structure below the self-floating base is a parabola with an upward opening, and the part inside and above the self-floating base is a straight line.

[0046] Specifically, the formula of the parabola with an upward opening of the inner petal component 201 is: ; the straight line of the inner petal component 201 forms an angle of 67.5° with the horizontal line, and the formula of the parabola with an upward opening of the outer petal component 202 is: ; the straight line of the outer petal component 202 forms an angle of 45° with the horizontal line.

[0047] Step 2: Preparation of the self-floating base support

[0048] First, a support self-floating base was modeled and designed using Solidworks software. The specific parameters are as follows: a cube with a length × width × height of 5 cm × 5 cm × 0.5 cm, and an inverted frustum with an upper top side length of 1.5 cm and a lower bottom side length of 17.07 cm was dug out at its center (the acute angle of the trapezoid in the side section is 45°, maintaining the same angle as the straight line of the outer petal component of the evaporator with the horizontal line), forming the mounting hole 101. The entire base is a hollow structure. Then, a foamed PLA low-density material (purchased from Shenzhen Tuozhu Technology Co., Ltd.) was used to start printing (Tuozhu X1C 3D printer). After completion, it can be removed and used after cooling, as Figure 4 shown.

[0049] Step 3: Preparation of the self-floating self-cleaning seawater evaporator

[0050] Through the dimensional planning of the evaporator and the base, the water absorption and evaporation component in the first step was perfectly combined with the support self-floating base in the second step, avoiding the influence brought by the additional use of adhesives such as glue. At the same time, since the water absorption and evaporation component is denser than water, a downward force will be generated, while the support self-floating base will receive an upward buoyancy force. Eventually, the two forces interact, making the water absorption and evaporation component firmly combined with the support self-floating base. Finally, the vertical distance between the top of the water absorption and evaporation component and the support self-floating base is 3 cm, and the vertical distance between the bottom of the water absorption and evaporation component and the support self-floating base is 1.3 cm, as Figure 2 、 3 shown.

[0051] Working principle:

[0052] As Figure 7 shown, the structural design of the water absorption and evaporation component can enhance the absorption of light through multiple reflections of sunlight, and can also allow natural wind to pass through the surface of the membrane unobstructed.

[0053] As Figure 8 shown, the salt generated by long-term seawater evaporation deposits on the surface of the evaporator. Since part of the evaporator is below the water surface, under the action of gravity, the precipitated salt can automatically fall off into the water body below, avoiding the efficiency decline caused by salt scaling in traditional evaporators, keeping the surface of the evaporator clean, and ensuring stable evaporation efficiency.

[0054] As Figure 9 shown, when the front of the evaporator is in the same direction as the wind direction (the direction indicated by the arrow in the figure), the wind can pass through the surface of the evaporator unobstructed and carry away the steam generated by the evaporation of the evaporator, reducing the saturated vapor pressure on the surface of the evaporator, thereby increasing the evaporation rate and evaporation efficiency. And when the wind blows towards the side of the evaporator, as Figure 10As shown, since the evaporator floats on the water surface by itself, the evaporator will rotate on its own to adapt to the direction of the wind. Thus, it can always keep the wind passing through the evaporator unobstructed.

[0055] Finally, the present invention gives the evaporation rates (kg m -2 h -1 ) comparison with three existing seawater evaporators, as shown in the following table:

[0056] ;

[0057] In the above table:

[0058] 1 Sun means: standard solar irradiance, i.e.: 1000 Wm -2 ;

[0059] 1 Sun - 0 Wind Speed means: under standard solar irradiance and wind speed of 0 m / s -1 ;

[0060] 1 Sun - 2 Wind Speed means: under standard solar irradiance and wind speed of 2 m / s -1 ;

[0061] 1 Sun - 4 Wind Speed means: under standard solar irradiance and wind speed of 4 m / s -1 .

[0062] The above three comparative examples are respectively from:

[0063] Comparative Example 1: Y. Liu, B. Luo, H. Liu, M. He, R. Wang, L. Wang, Z. Quan, J. Yu, X. Qin, 3D printed electrospun nanofiber-based pyramid-shaped solar vapor generator with hierarchical porous structure for efficient desalination (Based on 3D printed electrospun nanofiber pyramid-shaped solar vapor generator with hierarchical porous structure for efficient seawater desalination), Chemical Engineering Journal 452 (2023) 139402.

[0064] Comparative Example 2: Y. Chen, Y. Wang, J. Xu, M.R. Ibn Raihan, B. Guo, G. Yang, M.Li, H. Bao, H. Xu, A 3D Opened Hollow Photothermal Evaporator for HighlyEfficient Solar Steam Generation, Solar RRL 6(7) (2022) 2200202.

[0065] Comparative Example 3: Z. Zhang, W. Xu, J. Wang, M. Hu, D. Zhang, L. Jia, A. Kang,Y. Xi, X. Ye, S. Cheng, E. Sun, Y. Chen, Z. Wang, H. Lin, Q. Xiao, ImprovingSolar Vapor Generation by Eliminating the Boundary Layer Inhibition Effect ofEvaporator Pores, ACS Energy Letters 8(5) (2023) 2276-2283.

[0066] The present invention effectively utilizes dual driving of solar energy and wind energy to significantly improve the evaporation rate of the seawater evaporator, and at the same time effectively solves the problem of salt accumulation on the surface of the evaporator, greatly improving its long-term operation stability.

Claims

1. A self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy, characterized in that It includes a supporting self-floating base and a water-absorbing and evaporating component. An installation hole is provided at the center of the supporting self-floating base. The water-absorbing and evaporating component is inserted through the center of the supporting self-floating base and is closely fitted with the supporting self-floating base. The water-absorbing and evaporating component can absorb sunlight and utilize wind power to achieve seawater evaporation, and can prevent the accumulation of salts generated by seawater evaporation. The water-absorbing and evaporating component adopts an inner and outer petal structure, including an inner petal component and an outer petal component. The inner petal component and the outer petal component as a whole are respectively in a V-shaped structure, stacked up and down. And the V-shaped structure is a parabola with an upward opening in the part below the self-floating base and is a straight line in the part inside and above the self-floating base. The bottom of the water-absorbing and evaporating component extends out of the supporting self-floating base and is immersed in seawater, and the top of the water-absorbing and evaporating component exposes out of the supporting self-floating base and is exposed to the air.

2. The self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy according to claim 1, wherein The supporting self-floating base is made of foamed polylactic acid (PLA) material and has a hollow structure as a whole. An inverted frustum is dug out at its center to form an installation hole.

3. The self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy according to claim 1, wherein The density of the water-absorbing and evaporating component is greater than the density of water, so that the water-absorbing and evaporating component can be firmly combined with the supporting self-floating base.

4. The self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy according to claim 1, characterized in that, The upper opening parabola formula of the inner flap component is as follows: ; The upper opening parabola formula of the outer flap component is as follows: ; The straight line of the inner flap component forms an angle of 67.5 to 75° with the horizontal line, and the straight line of the outer flap component forms an angle of 45 to 67.5° with the horizontal line.

5. A self-floating and self-cleaning seawater evaporator driven by both solar energy and wind energy according to claim 1, wherein The preparation process of the water-absorbing and evaporating component is as follows: Step 1) Put an appropriate amount of polyvinylidene fluoride (PVDF) powder and graphene nanoplatelets (GNP) powder into an electrothermal blast drying oven at 65 - 75 °C and dry for 25 - 30 minutes to remove moisture and ensure complete drying. Step 2) Add 9.5 grams of dry PVDF into a beaker containing 50 milliliters of dimethylacetamide (DMA). Put the beaker into a thermostatic heating magnetic stirrer with heat collection, and stir in a water bath at 70 - 80 °C for 2.5 - 3.5 hours until PVDF is completely dissolved to obtain a colorless and transparent PVDF solution. Step 3) Add 0.5 grams of dry GNP into the PVDF solution, continue to stir in a water bath at 70 - 80 °C for 2.5 - 3.5 hours. After that, take it out and perform ultrasonic dispersion for 25 - 30 minutes to obtain a uniformly dispersed black composite solution. Then cover the solution with a breathable membrane and let it stand at room temperature for 7 - 9 hours to remove bubbles for further use. Step 4) After the defoaming process is completed, use a syringe to inject the black composite solution into the mold until it is completely filled. After the mold is sealed, pre-cool it in a refrigerator at about 3 - 5 °C for 5 - 7 hours to prevent cracking during the actual freezing process. After pre-cooling, put the mold into the cold trap of a vacuum freeze dryer and freeze it at - 65 - 70 °C for 1.5 - 2.5 hours. Step 5) After complete freezing, obtain a 3D solid composite by disassembling the mold. Step 6) Put the solid composite back into the cold trap and freeze-dry it at - 65 - 70 °C and 0.1 Pa for 2.5 - 3.5 hours to sublime the DMA solvent and form a 3D water-absorbing and evaporating component.

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